The present invention relates to a fluid injection nozzle and, more specifically, to an injection nozzle section of an electromagnetic fuel injection valve that delivers fuel by injection to an internal combustion engine of an automobile.
Generally, in the fuel injection nozzle to be used in the internal combustion engine, a valve member is slidably received in a guide hole formed axially in a valve main body and an injection hole opened in a tip end portion of the valve main body is opened and closed by the vertical movement of the valve member. For this reason, the valve member is controlled accurately in its lift in opening the valve for the purpose of obtaining an appropriate fuel injection amount.
Examples of the prior art include a fluid injection nozzle disclosed in Japanese Patent Unexamined Publication No. 61-104156 in which a large number of slit-like orifices are provided in front of the injection hole so that, by making fuel coming from the injection hole pass through the slit-like orifices, it is possible to obtain a spray of fuel atomized and dispersed through over a wide angle.
Further, U.S. Pat. No. 4,907,748 discloses the one in which a plurality of silicon plates are provided in front of the injection hole. An accurate fuel path hole pattern can be formed by making use of the silicon plates, and accordingly, the fuel flow can be controlled.
Moreover, U.S. Pat. No. 4,647,013 discloses a fluid injection nozzle in which a silicon flat plate having an orifice for controlling the fuel flow is provided in front of the injection hole.
As disclosed in Japanese Patent Unexamined Publication No. 61-104156 described above, in order to promote the atomization of the spray of fuel, various shapes of injection holes have been proposed heretofore.
However, with the shapes of injection holes disclosed in the prior arts, it has been difficult to atomize the fuel sufficiently.